Transaction cards are a convenient and accepted means of accessing services and financial resources. In order for these cards to be accepted internationally the data format of these cards has been agreed upon. While these standards offer many advantages, the standards pose obstacles for applications not initially intended or considered by the authors of the standards. The present invention describes a method to maintain the data structure described by ISO 7811/2 while encoding information which, in its usual form, would not comply to the standard.
The application of primary importance is the ability to store information on the magnetic stripe of a transaction card sufficient to reconstruct a recognizable image. Credit card fraud is a significant problem in the credit industry, and various means and methods have been attempted to reduce the fraudulent use of credit cards. One of these methods encodes the digital image of the cardholder ("Method and Apparatus for Credit Card Verification"; U.S. patent application Ser. No. 08/019,538; invented by Lawrence A. Ray and Richard N. Ellson; and filed on Feb. 18, 1993 now U.S. Pat. No. 5,321,751 issued on Jun. 14, 1994. ). Encoding this image requires data compression of an original image. The compression algorithm is described in U.S. patent application Ser. No. 08/145,051 entitled "Method and Apparatus for Image Compression, Storage and Retrieval on Magnetic Transaction Cards"; invented by Lawrence A. Ray, Richard N. Ellson, and Bhavan R. Gandhi; filed on even date herewith; and assigned to the assignee of the present Application). The encoded data from this method generates a string of binary digits, and this digit string must be written onto a magnetic stripe in a manner compatible with ISO standards and in particular standard ISO 7811/2.
A need has therefore been felt for apparatus and a procedure by which the raw binary bit string can be converted to a format which is in compliance with international standards which cover magnetic financial transaction cards. This compliance includes the transmission of information which would otherwise be encoded by a reserved character or value.